1,102 research outputs found
Shock Theory of a Bubbly Liquid in a Deformable Tube
Shock propagation through a bubbly liquid filled in a deformable cylindrical tube is considered. Quasi-one-dimensional
bubbly flow equations that include fluid-structure interaction are formulated, and the steady shock
relations are derived. Experiments are conducted in which a free-falling steel projectile impacts the top of an air/water
mixture in a polycarbonate tube, and stress waves in the tube material are measured. The experimental data indicate
that the linear theory cannot properly predict the propagation speeds of shock waves in mixture-filled tubes; the shock
theory is found to more accurately estimate the measured wave speeds
Electron Mass Enhancement due to Anharmonic Local Phonons
In order to understand how electron effective mass is enhanced by anharmonic
local oscillation of an atom in a cage composed of other atoms, i.e., {\it
rattling}, we analyze anharmonic Holstein model by using a Green's function
method. Due to the evaluation of an electron mass enhancement factor , we
find that becomes maximum when zero-point energy is comparable with
potential height at which the amplitude of oscillation is rapidly enlarged.
Cooperation of such quantum and rattling effects is considered to be a key
issue to explain the electron mass enhancement in electron-rattling systems.Comment: 3 pages, 3 figures, to appear in J. Phys. Soc. Jpn. Suppl.
(Proceedings for International Conference on Heavy Electrons
Shock propagation through a bubbly liquid in a deformable tube
Shock propagation through a bubbly liquid contained in a deformable tube is considered. Quasi-one-dimensional mixture-averaged flow equations that include fluid–structure interaction are formulated. The steady shock relations are derived and the nonlinear effect due to the gas-phase compressibility is examined. Experiments
are conducted in which a free-falling steel projectile impacts the top of an air/water mixture in a polycarbonate tube, and stress waves in the tube material and pressure
on the tube wall are measured. The experimental data indicate that the linear theory is incapable of properly predicting the propagation speeds of finite-amplitude waves
in a mixture-filled tube; the shock theory is found to more accurately estimate the measured wave speeds
Realization of Strong Coupling Fixed Point in Multilevel Kondo Models
Impurity four- and six-level Kondo model, in which an ion is tunneling among
four- and six-stable points and interacting with surrounding conduction
electrons, are investigated by using the perturbative and numerical
renormalization group methods. It is shown that purely orbital Kondo effects
occur at low temperatures in these systems which are direct generalizations of
the Kondo effect in the so-called two-level system. This result offers a good
explanation for the enhanced and magnetically robust Sommerfeld coefficient
observed in SmOs_4Sb_12 and some other filled-skutterudites.Comment: 3 pages, 3 figures, for proceedings of ASR-WYP-2005. To be published
in Journal of Physical Society Japan supplemen
Universality in heavy-fermion systems with general degeneracy
We discuss the relation between the T^{2}-coefficient of electrical
resistivity and the T-linear specific-heat coefficient for
heavy-fermion systems with general , where is the degeneracy of
quasi-particles. A set of experimental data reveals that the Kadowaki-Woods
relation; , collapses
remarkably for large-N systems, although this relation has been regarded to be
commonly applicable to the Fermi-liquids. Instead, based on the Fermi-liquid
theory we propose a new relation;
with and .
This new relation exhibits an excellent agreement with the data for whole the
range of degenerate heavy-fermions.Comment: 2 figures, to appear in Phys. Rev. Let
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